Tag: gdal

Geospatial Power Tools Reviews [Book]

Thinking of buying my latest book?  We’ve finally got a few reviews on Amazon that might help you decide.  See my other post for more about the book.  Buy the PDF on Locate Press.com.

Reader Reviews

Geospatial Power Tools book cover
From Amazon.com

5.0 out of 5 stars This book makes a great reference manual for using GDAL/OGR suite of command line …,
January 24, 2015 By Leo Hsu
“The GDAL Toolkit is chuckful of ETL commandline tools for working with 100s of spatial (and not so spatial data sources). Sadly the GDAL website only provides the basic API command switches with very few examples to get a user going with. I was really excited when this book was announced and purchased as soon as it came out. This book makes a great reference manual for using GDAL/OGR suite of command line utilities.
Several chapters are devoted to each commandline tool, explaining what its for, the switches it has, and several examples of how to use each one. You’ll learn how to work with both vector/(basic data no vector) data sources and how to convert from one vector format to another. You’ll also learn how to work with raster data and how to transform from one raster data source to another as well as various operations you can perform on these.”

 

Continue reading Geospatial Power Tools Reviews [Book]

Converting Decimal Degree Coordinates

Converting Decimal Degree Coordinates to/from DMS Degrees Minutes Seconds

cs2cs command from GDAL/OGR toolset (gdal.org) - allows robust coordinate transformations.
cs2cs command from GDAL/OGR toolset (gdal.org) – allows robust coordinate transformations.

If you have files or apps that have to filter or convert coordinates – then the cs2cs command is for you.  It comes with most distributions of the GDAL/OGR (gdal.org) toolset.  Here is one popular example for converting between degrees minutes and seconds (DMS) and decimal degrees (DD).

Geospatial Power Tools book coverThe following is an excerpt from the book: Geospatial Power Tools – Open Source GDAL/OGR Command Line Tools by me, Tyler Mitchell.  The book is a comprehensive manual as well as a guide to typical data processing workflows, such as the following short sample…

Input coordinates can come from the command line or an external file. Assuming a file containing DMS (degree, minute, seconds) style, looks like:

124d10'20"W 52d14'22"N
122d20'05"W 54d12'00"N

Use the cs2cs command, specifying how the print format will be returned, using the -f option. In this case -f “%.6f”
is explicitly requesting a decimal degree number with 6 decimals:

cs2cs -f "%.6f" +proj=latlong +datum=WGS84 input.txt

Example Converting DMS to/from DD

This will return the results, notice no 3D/Z value was provided, so none is returned:

-124.172222 52.239444 0.000000
-122.334722 54.200000 0.000000

To do the inverse, remove the formatting option and provide a list of values in decimal degree (DD):

cs2cs +proj=latlong +datum=WGS84 inputdms.txt
124d10'19.999"W 52d14'21.998"N 0.000
122d20'4.999"W 54d12'N 0.000

Geospatial Power Tools is 350+ pages long – 100 of those pages cover these kinds of workflow topic examples. Each copy includes a complete (edited!) set of the GDAL/OGR command line documentation as well as the following topics/examples:

Workflow Table of Contents

  1. Report Raster Information – gdalinfo
  2. Web Services – Retrieving Rasters (WMS)
  3. Report Vector Information – ogrinfo
  4. Web Services – Retrieving Vectors (WFS)
  5. Translate Rasters – gdal_translate
  6. Translate Vectors – ogr2ogr
  7. Transform Rasters – gdalwarp
  8. Create Raster Overviews – gdaladdo
  9. Create Tile Map Structure – gdal2tiles
  10. MapServer Raster Tileindex – gdaltindex
  11. MapServer Vector Tileindex – ogrtindex
  12. Virtual Raster Format – gdalbuildvrt
  13. Virtual Vector Format – ogr2vrt
  14. Raster Mosaics – gdal_merge